hari

We have installed Avtech AVC761Z(EU)-B , 4 CH MPEG 4 DVR, in our organisation.WORKS FINE with 4 cameras Only problem is that when we have to backup. It has option of Backup through USB. But it will accept USB pendirve only till 512 MB. It cannot recognize higher capacity pendrives. Can somebody give me link where I can find the firmware upgrade for the same or some other way to back up through USB pendrive. Also the backed up video when replayed is replayed in slow motion. How to solve this also?